We will determine the cellular DNA distribution of colonic adenocarcinomas by flow cytometric analysis of nuclei prepared from tissue obtained at surgery. We will determine the prognostic significance of diploid vs. nondiploid DNA distribution of tumors by prospective correlation with patient survival or time to tumor recurrence after surgery. We will follow the patients postsurgically by determining the levels of serum CEA and galactosyl II transferase every three months in addition to the customary clinical follow-up procedures for tumor recurrence. We will follow 150 patients per year with tumors resected for cure at Montefiore Medical Center. We will determine the mean postsurgical disease-free interval and survival time of patients with diploid or nondiploid tumors matched for age, stage of disease and tumor size, who have been resected for cure. We will determine whether cellular DNA distribution is a significant and useful discriminant in distinguishing colon cancer patients with very aggressive malignant tumors who should receive more intensive follow-up and perhaps different treatment regimens. Our preliminary study on a small number of patients suggests that differences in DNA distribution are of prognostic value in colon cancer. Of 32 patients with grades B, C and D tumors, 13/13 patients with nondiploid tumors were dead of disease at 5 years while 19/19 with diploid tumors were alive at 5 years. Thirteen of these with B & C stage tumors at surgery remained free of disease. The present prospective study will further evaluate the significance of this observation. The value of galactosyl transferase II as an adjunct to CEA will also be evaluated.